Trimming mechanisms for sewing machines



Jan. 10, 1956 H. RITTER TRIMMING MECHANISMS FOR SEWING MACHINES 2 Sheets-Sheet 1 Filed Jan. 16, 1953 INVENTOR. flirman .Qzltter BY ATTORNEY Jan. 10, 1956 H. RITTER TRIMMING MECHANISMS FOR SEWING MACHINES Filed Jan. 16, 1953 2 Sheets-Sheet 2 IN V E 'gTOR. @Zrman iii-en ATTORNEY WITNESS ?77 United States Patent O" TRIMMING MECHANISMS FOR SEWING MACHINES Herman Ritter, Cranford, N. J., assignor to The Singer Manufacturing Company, Elizabeth, N. 1., a corporation of New Jersey Application January 16, 1953, Serial No. 331,643 3 Claims. or. 112- 123 The present invention relates to sewing machines and has for a primary object to provide a sewing machine with an improved trimming mechanism.

. More specifically, it is an object of the present in vention to provide an improved trimming mechanism which is especially adapted for embodiment in an auto matically lubricated sewing machine.

It is a further object of the present invention to provide an improved means for throwing into and out of operation a trimming mechanism of a sewing machine, and particularly for a trimming mechanism of an automatically lubricated sewing machine.

1 Having in mind the above and other objects that will be evident from an understanding of this disclosure, the invention comprises the devices, combinations and arrangements of parts as illustrated in the presently preferred embodiment of the invention, which is hereinafter set forth in such detail as to enable those skilled in the art readily to understand the function, operation, construction and advantages of it when read in conjunc tion with the accompanying drawings in which:

Fig. 1 is a fragmentary vertical section view particularly of the head together with portions of the bed and bracket-arm of a sewing machine embodying the present invention.

Fig. 2 is a vertical section view taken substantially on the line 2-2 of Fig. 1.

Fig. 3 is a horizontal section view taken substantially on the line 33 of Fig. 1.

Fig. 4 is a vertical sectional view taken substantially on the line 44 of Fig. 1.

Fig. 5 is a vertical section view taken substantially on the line 55 of Fig. 3.

Fig. 6 is a vertical section view taken substantially on the line 6-6 of Fig. 4.

As illustrated in the drawings, the present invention is embodied in a conventional sewing machine having a bed 1 and an overhanging bracket-arm 2 that terminates in a head 3, the open end of which head is closed by a removable face-plate 4. An aperture 5 is provided in the upper portion of the bracket-arm to permit access to the internal mechanism, which aperture is closed by a cover-plate 6.

A presser-bar 7, and a needle-bar 8 carrying a needle 9 at its lower end, are journaled for vertical reciprocation in the head 3 in the usual manner. The presser-bar 7 may be raised or lowered by means of a hand-lifter lever 10 or by a knee or foot actuated lever 11 through any appropriate well-known connections. Journaled longitudinally of the bracket-arm 2 is an arm-shaft 12, one of the bearings for which shaft is illustrated at 13. At its end adjacent the head 3, the shaft 12 carries a counterbalanced crank 14 which is connected to the needle-bar 8 in any suitable manner, whereby the needlebar will be reciprocated upon rotation of the shaft 12. It will be understood that the shaft 12 is connected at its opposite end to a suitable source of power and that the needle 9 is adapted to cooperate with suitable loop- 2,730,059 Patented Jan. 10, 1956 2 taker mechanism below the bed 1, whereby the shaft 12 will be rotated to actuate the needle in timed relation with respect to the loop-taker to efiect stitch formation, all of which mechanism may be conventional and therefore is not shown in the drawings nor described herein.

Also journaled for vertical reciprocation within the head 3 is a trimmer-bar 15 which is positioned between the needle-bar 8 and presser-bar 7.. At its lower end, the trimmer-bar 15 carries a bracket 16 secured thereto for adjustment transverse to the line of stitch formation by means of screws 17 which extend through elongated slots 18 in the bracket 16 and are threaded into the trimmer-bar 15. The bracket 16 includes a depending arm 19 to the one face of which is secured a trimmerblade 20 having a cutting edge 21. The blade 20 is clamped and held between a plate 22 and the bar 15 by means of screws 23 which extend through a vertical elongated slot 24 in the blade 20 whereby the same may be adjusted vertically. The trimmer-blade 20 is adapted to cooperate with the cutting edge of a stationary ledger blade 25 which is adjustably secured to a conventional throat-plate 26 by means of a screw 27 that extends through an elongated slot 28 in the ledger blade 25 and is threaded into the throat-plate 26. In the usual manner, the throat-plate is removably carried by the bed 1. The mechanism for imparting vertical reciprocation to the trimmer-bar 15 includes a countershaft 29 arranged parallel to the arm-shaft 12, and vertically above and to the rear of the same, which countershaft is journaled in suitable bearings 30 fixed as by screws 31 in internal lugs 32 integral with the machine frame. At one end, the countershaft 29 is embraced by the hub or strap portion 33 of. a crank arm 34 which, at its free end, is pivotally connected as by a crank pin 35 to the rec end of a pitman 36, which in turn, includes a strap portion 37 that embraces an eccentric 38 integral with a hub portion 39 fixed to the shaft 12 as by a screw 40. Also mounted upon the shaft 12 is a counterweight 41 for dynamically balancing the moving elements. From the above it Will be seen that, upon rotation of the armshaft 12, oscillation will be imparted to the countershaft 29 through the eccentric 38, pitman 36 andcrank-arm 34.

At its end opposite to that carrying the crank-arm 34,

the .c'ountershaft 29 is embraced by the strap 42 of a crank-arm 43, the free end of which is formed as a sleeve 44 having a bore 45. As best seen in Fig. 6, the bore 45 is adapted to slidably receive a pin or plunger 46 having a reduced intermediate portion 47 and a threaded end 48. A coil spring 49 encircles the reduced portion 47 and is compressed between the shoulder formed on the pin 46 by the reduced portion 47 and the shoulder formed by the bore 45 which includes a small diameter end portion 50 adapted to slidably receive the reduced portion 47 of the pin 46. The crank-arm 43 is so dimensioned and arranged With respect to the countershaft 29 that the pin 46 carried at the end thereof will be biased by the spring 49 into engagement with the edge of the trimmer-bar 15, which is provided with a notch 51 that is adapted to receive the forward end of the pin. Thus the pin 46 normally couples the trimmer-bar 15 to the crank-arm 43 whereby, upon oscillation of the countershaft 29, recipro Qeeast g the rimmer-bar. .5 aadat heother nd. one,

upper portion of the head of. the machine. Thus, when the pin 46 is retracted fronuthe notch 51, the spring 51a wilhwithdravsr. the, trimmer-bar. 1-5 ,upwardly to. its inoperatiye position as; illustrated. in dotted: lines in Fig. l, inrwhi hlpQsitionthe. oscillation of the. crankearm- 43 will tQt; effect; reciprocation of the. trimmer-bar since. the pin MS- merely. abuts againstthe edge of the trimmer-bar and will slide relative thereto. To restore the trimmerbar. 15- to its operative position it.is only necessary to man ually. depress. thesarneuntil the pin 46,. under the action of its spring. 49,- snaps intothe notch 5-1. To facilitate depressing the..ti:immer-bar there is provided athumb piece-.542 securedtothe arm 19 of-thebracket 16by means of; screw 53. that passes through one face of a Ufshaped yQke element, 54 integralawith the thumbpiece and-bent at arightangle thereto.

Means are. provided; for manually withdrawing the pin 46 from the notch 51 and thus disabling'the trimming mechanism, said means including a lever 55 pivoted intermediate. its ends on a horizontal pivot pin 56 having. its ends fixed in the spaced walls of a U-shaped bracket- 57 securedto the face-plate 4, as by screws 58 passing through fiangeson the bracket 57. The. upper endof the lever 55 comprises a fork 59 having the opposed. tines thereof passing on either side of and closely adjacent to the outer faces of the sleeve 44 which houses the, pin 46. A nut 60 is screwed onto the threaded end 48 of -the pin andalock nut 61 is tightenedthereagainst.

Theheadof the nut 60 is enlarged or may carry a washer so that the tines of the fork- 59 may abut the reagainst when the'lever 55 is pivoted about the pin 56 thus to retract the pin 46. A spring 62 is used to urge the lever 55 in that direction of rotation away from the direction in which the pin 46 is retracted. To pivot the lever 55 in the opposite direction against the action of the spring62, there isprovided plunger 63 having a reduced portion 64 slidably projecting through the face-plate 4 in position to engagethe end ofthe lever 55. The reduced portion 64 is provided with a peripheral snap-ring 65 which serves as a stop to limit withdrawal of the plunger 63 and thus limit the action of the spring 62 From. the above, it will be understood that depressing the plunger63 will release the trimmer-bar 15 whichf willthen. be moved to inoperative position by the spring. 51a. To. restorethe same to its normal operative position itis only necessary to-depress the hand piece 52 and thus the trimmer-bar 15 until the pin 46 under the action of spring49 snaps into the notch 51; Y

It isto be understood that the disclosed machine is adapted to be automatically lubricated in any desirable well known manner, such as disclosed in applicants copendingapplication Serial No. 732,173, filed March 4, 1947. For the sake of clarity, sincesuch lubricating expedients are amend Well-known and since the present invention is not'limited to any particular arrangement, the lubrication features have not been specifically shown.

However, it should be noted that the bracket-arm 2 and head-Skogether with the cover-plate fiand face-plate 4 dcfine a. substantially closed, oil-tight compartment in which the internal 7 mechanisms are adapted to operate. The present trimmeri throw-outdevice is designed specifically to; preserve the oil-tight, character of this compartment while including 7 a manually operated means outside there offer disconnectingthe,trimmer drive connections inside will snggestthemselvesito. thosev skilled in the. art. Howogen.itzistotbqunderstood that-the present disclosure re- Numerous alterations of the structure herein disclosed.

te L9,. a. preferred embodiment of. my invention, which is for purposes of illustration only and not to be construed as a limitation of the invention. All such modifications which do not depart from the spirit of the invention are intended to be included within the scope of the appended claims.

Having thusset forth. the nature of the; invention, what I claim herein is:

1. In a sewing machine having a bracket-arm terminating in a head and a faceplate closing an open end of said head'to. definea closed compartment, a reciprocable trimmer-bar and an actuating element therefor mounted within 'said closed, compartment, a releasableconnection between said trimmer-bar and said actuating element comprising a slidable pin carried by saidactuating element for sliding movement relative thereto and a cooperating notch formed in said trimmer-bar, 'a lever piv t'4 lly mounted. internally of saidclosed compartment upon said facesplate and operatively connected to said pin for retracting the same upon pivotalmovement of said lever, and a plunger carried by said-face-plate for axialsliding movement therethrough and arranged substantially par allel to said pin, the end of said plunger within said closed compartment operatively engaging said lever to pivot the same upon sliding movement of said plunger and the end of said plunger externally of; said closed compartment being adapted for manual actuation to impart sliding movementstosaid plunger.

2. In a sewing machine having a bracket-arm terminating in a. head ancia faceplate closing an open end, of said head to define a closed compartment, a recipro-I cable trimmer-bar and an actuating element therefor mounted within said closed compartment, a releasable connection between said trimmer-bar and said actuating element comprising aslidable pin carried by said actuatiing element for sliding movement relative thereto and a cooperating notch formed in said trimmer-bar, said pin being provided with a peripherally reduced portion, a lever pivotally mounted intermediate its ends upon said face-plate within said closed compartment to provide opposite lever-arms, one of said arms being folkqd and. adapted to be received within the peripherally reduced portion of said pin to operatively connect said lever to said pin for retracting the same upon pivotal movement of saidlever, anda plunger carried by said face-plate for axial sliding movement therethrough and arranged substantially parallel to said pin, the end of saidplunger within said closed compartment operativelyengaging. the other of said lever-arms for pivoting said lever uponsliding movement of said plunger and the end of saidttlunger externally of said closed compartmentbeing adaptedlf manual actuation to impart sliding movements to said plunger.

3. In a sewing machine having a bracket-arm ter inieating in aheadand a face-plate closing, an openendof said head to form a substantially closed.'compartment aj trimming mechanism comprisinga trimmer-bar monnted within said head for longitudinal. reciprocation, an oscil; latory shaft journaled within said bracketarm. long i-, tudinally of the same and, extending into said closed compartment, a cranl -arm secured toisaid,shafpwithin; said closed compartment, and a releasable. connection, between said crank-arm and trimmer-barcomprising a slidablepin carriedby said crank-armfor sliding move.- ment relativetheretotand a cooperating notchformedrin said trimmer-bar, a lever pivotally mountedupon said face-plate within said closed compartment and opera{ lively connected'to said pin for retracting the same upon pivotal movement of said lever, and a plunger carriedby said face-plate for axial sliding movement. there; through and arrangedsubstantially parallel to said pin, the end-of said-plunger within said closed comp operatively engagin said lever topivot the sa mup}; sliding moveme'ntof' said plunger and the end of said References Cited in the file of this patent UNITED STATES PATENTS 361,501 Diehl Apr. 19, 1887 6 Hill et al. Feb. 19, 1901 Neely July 24, 1906 Altstock Sept. 24. 1907 Brussell July 28, 1936 

